Cluster analysis is an exploratory data analysis technique, encompassing a number of different algorithms and methods for sorting objects into groups. Cluster analysis requires the analyst to make choices about dissimilarity measures, grouping algorithms, etc., and these choices are difficult to make without an understanding of their theoretical implications and a very good understanding of the data. This chapter provides an introduction to the distance measures and clustering algorithms most commonly used for cluster analytic work. Different from Baayen (2008), Johnson (2008) and Gries (2009), its main aim is to equip the researcher with at least a basic understanding of what is happening behind the scenes when a dataset is explored with the help of a particular cluster analytic technique.